<div class="eI0">
  <div class="eI1">Modell:</div>
  <div class="eI2"><h2><a href="http://dd.meteo.gc.ca/doc/LICENCE_GENERAL.txt" target="_blank">CMC</a>: "Data Source: Environment and Climate Change Canada"</h2>
  <br><h2>Times Series from the CMC Ensemble</h2></div>
 </div>
 <div class="eI0">
  <div class="eI1">Aktualisierung:</div>
  <div class="eI2">2 times per day, from 10:00 and 23:00 UTC</div>
 </div>
 <div class="eI0">
  <div class="eI1">Greenwich Mean Time:</div>
  <div class="eI2">12:00 UTC = 13:00 MEZ</div>
 </div>
 <div class="eI0">
  <div class="eI1">Aufl&ouml;sung:</div>
  <div class="eI2">1.0&deg; x 1.0&deg;</div>
 </div>
 <div class="eI0">
  <div class="eI1">Parameter:</div>
  <div class="eI2">Sea Level Pressure in hPa (solid lines) and equivalent potential temperature at 700 hPa (dashed and coloured)</div>
 </div>
 <div class="eI0">
  <div class="eI1">Beschreibung:</div>
  <div class="eI2">

The equivalent potential temperature map - updated every 6 hours - shows the modelled equivalent 
potential temperature at the 850hPa level. The equivalent potential temperature is commonly referred 
to as Theta-e (&#952;e). &#952;e is the temperature of a parcel of air after it was lifted until 
it became saturated with water vapour (adibatically). When this parcel becomes saturated and 
condensation begins, the process of condensation releases latent heat into the surrounding air. 
This latent heat further warms the air making the air even more buoyant. We refer to this as a moist 
adiabatic or saturated adiabatic process. Moist adiabatic expansion increases the instability of the parcel. 
If this process of moist adiabatic expansion continues, all of the water may condense out of the rising 
parcel and precipitate out, yielding a dry parcel, and is dropped adiabatically to an atmospheric pressure of 
1000 hPa. The potential temperature of that new dry parcel is called the equivalent potential temperature 
(&#952;e) of the original moist parcel
<BR>
In meteorology &#952;e is used to indicate areas with unstable and thus positively buoyant air. The &#952;e of 
an air parcel increases with increasing temperature and increasing dewpoint as for the latter more latent 
heat that can be released. Therefore, in a region with adequate instability, areas of relatively high &#952;e 
(called &#952;e ridges) are often the burst points for thermodynamically induced thunderstorms and MCS's. 
&#952;e ridges can often be found in those areas experiencing the greatest warm air advection and moisture advection.
(source: <a href="http://www.theweatherprediction.com" target="_blank">the weather prediction</a>
Keep in mind that if a strong cap is in place, convective storms will not occur even if &#952;e is high.
<BR>
As different origins of airmasses largely determine their own &#952;e,
one can use this parameter as a marker. Fronts are easily seen as steep gradients in
&#952;e. The boundary layer &#952;e shows where fronts are located near the surface,
while 700 hPa &#952;e shows where they are near the 3000 m level. In winter it occurs
often that warm fronts do not penetrate into the heavy, cold airmass near the surface.
    
  </div>
 </div>
 <div class="eI0">
  <div class="eI1">NWP:</div>
  <div class="eI2">Numerische Wettervorhersagen sind rechnergest&uuml;tzte Wettervorhersagen. Aus dem Zustand der Atmosph&auml;re zu einem gegebenen Anfangszeitpunkt wird durch numerische L&ouml;sung der relevanten Gleichungen der Zustand zu sp&auml;teren Zeiten berechnet. Diese Berechnungen umfassen teilweise mehr als 14 Tage und sind die Basis aller heutigen Wettervorhersagen.<br><br>
In einem solchen numerischen Vorhersagemodell wird das Rechengebiet mit Gitterzellen und/oder durch eine spektrale Darstellung diskretisiert, so dass die relevanten physikalischen Gr&ouml;&szlig;en, wie vor allem Temperatur, Luftdruck, Windrichtung und Windst&auml;rke, im dreidimensionalen Raum und als Funktion der Zeit dargestellt werden k&ouml;nnen. Die physikalischen Beziehungen, die den Zustand der Atmosph&auml;re und seine Ver&auml;nderung beschreiben, werden als System partieller Differentialgleichungen modelliert. Dieses dynamische System wird mit Verfahren der Numerik, welche als Computerprogramme meist in Fortran implementiert sind, n&auml;herungsweise gel&ouml;st. Aufgrund des gro&szlig;en Aufwands werden hierf&uuml;r h&auml;ufig Supercomputer eingesetzt.<br><br>
<br>Seite „Numerische Wettervorhersage“. In: Wikipedia, Die freie Enzyklop&auml;die. Bearbeitungsstand: 21. Oktober 2009, 21:11 UTC. URL: <a href="http://de.wikipedia.org/w/index.php?title=Numerische_Wettervorhersage&amp;oldid=65856709" target="_blank">http://de.wikipedia.org/w/index.php?title=Numerische_Wettervorhersage&oldid=65856709</a> (Abgerufen: 9. Februar 2010, 20:46 UTC) <br>
</div></div>
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